i bought a sheep dog from an old chap selling them off a while back and ive regretted it ever since! all i wanted was a chum but hes my enemy. he doesnt listen to my commands, hes chewed up my house, ruined the carpets and has even physically sunk his teeth into me on several occurances. its got to the point where i dread coming home on an evening! shall i just get rid of him or perservere!? help me!

It's entirely up to you whether you "just" get rid of this dog or perservere!!
From your remarks, you obviously have no idea how to go about training a dog, how a dog thinks or why a dog acts as he does.
He doesn't listen to your commands because either:
1. You haven't made it clear to him what you expect from him.
2. You haven't given him any incentive (praise, treats, toys) to obey you.

I would suggest you need professional help with this dog - at least take him to a training class where he can be assessed & you can be taught how to train him
Stop looking on him as your "enemy" & start trying to think of him as a dog who needs to be taught how to behave.

I assume this dog is a Border Collie type?  They are an extraordinary breed - normally very sensitive, but with a high need for things to do - in the abscence of any sort of direction they will often find things of their own - hence the chewing and general distruction :(  How long is he left alone each day?  Do you leave any toys or chews for him?  How are you training him?  Do you have any idea how old he is??
As Anwen says - really you are the only one who can make the decision in the end.

Hi you dont say if it was a pup/adult? have you had it checked at vets what colour is it as some can be deaf? if we know what age it is we can advise you better.